Pressure relief valves for the cabin of a motor vehicle are well known. Sedans and sport utility vehicles may include a plurality of pressure relief valves to allow the exhausting of air from the cabin or to relieve pressure during a sudden increase of pressure in the cabin. Furthermore, the valves may allow a free flow of air for ventilation systems to provide efficient cooling and heating of the passenger compartment.
Generally, the valves may include a plurality of relatively flexible flaps or louvers that may rest on a gate system or other such structure. The gate system allows the relatively flexible flaps to act as a one-way check or reed valve, so that the flow of air may be quickly exhausted without encountering a significant obstruction, while allowing the flaps to recover to an initial position when there is no flow, so as to restrict unwanted backflow of unfiltered air into the passenger compartment.
Air exhausters may provide a controlled air relief system to maintain the balance that the HVAC system requires. When the HVAC system is in fresh air mode and outside ambient air is being processed, an equivalent airflow mass may be removed from the vehicle by air exhausters. The body panels and seals typically do not provide enough controlled venting capacity to handle the HVAC airflow requirements. Exhausters may be installed in a rearward area of the body of the vehicle to furnish controlled airflow vent paths that may reduce interior cabin pressures and improve airflow distribution from the front of vehicle to the rear of vehicle. Exhausters also provide airflow relief paths which help facilitate door closing by reducing efforts as well as assisting in airbag deployment.
The use of air exhausters may aid in reducing the noise level in the vehicle by reducing aspiration noise. Preferably, at least two body exhausters may be located at the rearmost corners of the vehicle which may be fed via a somewhat torturous airflow path to provide an effective airflow path while minimizing noise.
Air exhausters of the flap type may not seal tightly enough to prevent some inflow of exhaust gases, odors, other contaminants or outside noise. These devices typically are molded of injection molded rubber and plastic having a relatively high density, thus contributing weight to the vehicle.
What is needed is an air exhauster of light weight which can filter the inflow of contaminated air, reduce noise intrusion and not substantially restrict the outflow of air from the vehicle cabin.